Fluid gauge nozzle



Oct. 29, 1940. W E 2,219,406 FLUID GAUGE NOZZLE I Filed Jan. 24, 1938 2. Z=' ig.3. H

as 4a 19 {a INVENTOR,

MORRIS C. WH/T BY 4AM A TTORNEYS.

Patented Oct. 29, 1940 vireo STATES PATENT OFFICE 4 Claims.

This invention relates to gauges for indicating fluid pressure or flow, and particularly to gauges of the type described in my copending application, Serial No. 744,937, filed September 21, 1934, now Patent No. 2,124,096, granted July 19, 1938, wherein the indicating mechanism comprises a restrained turbine, i. e., a rotor whose movement is controlled by a spring, against which rotor is directed a jet of the fluid whose pressure or flow is to be measured.

For certain purposes, such as tire pressure gauges, the nozzles used to direct the fluid against the rotor in gauges of this type, should be extremely small, 1. e., of the order of magnitude of a circular aperture of from siX to ten thousandths of an inch in diameter. The moment imposed upon the rotor by'the jet is nearly directly proportional to the cross-sectional area of the aperture, and it is difiicult to form apertures of such minute size with the degree of uniformity desired by the ordinary processes of drilling and breaching. In manufacturing gauges or meters of this character it is therefore necessary individually to calibrate each one, and to accom- 5 modate any variations in cross-section of the aperture by changing its angle with relation to the rotor, or by varying the tension of the restraining spring, or both. The first of these operations is simple, but where the change of angle is relatively great itmay be accompanied by variations from uniformity in the scale. Change of spring tension is somewhat more difficult of accomplishment, although it is entirely possible,

This invention relates to the structure of the nozzle and the formation of the metering aperture therein, and includes among its objects the provision of a nozzle wherein the aperture is adjustable so that its lumen may be varied through a very wide range, in order that the same nozzle may be used for gauges having widely different ranges; the provision of a nozzle which permits varying both the angle and the area of the fluid stream directed against the rotor; and the provision of a nozzle wherein an aperture having the required degree of precision may be formed accurately and with tools which are more rugged and controllable than the drills or broaches which must be used with the type of aperture shown in my previous application above referred to.

Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, but I do not limit myself to the embodiment of the invention herein described as various forms may be adopted within the scope of the claims.

Referring to the drawing:

Figure 1 shows a front elevation of a line-service-tire gauge embodying my invention, the dial of the gauge being shown as broken away in order to indicate the positioning of the nozzle with respect to the rotor.

Figure 2 is an enlarged sectional View of the nozzle of this invention, the plane of section being indicated by the line 22 of Figure 1.

Figure 3 is a similar sectional View of the nozzle taken in a plane normal to that of Figure 2, the plane of section of this drawing being indicated by the line 33 of Fig. 2.

Figure 4 is a fragmentary sectional view through a portion of the frame, rotor, and nozzle, the plane of section being parallel to the plane of view in Fig. 1, and indicated by the line 4-4 of Fig. 2.

Figures 5 and 6 are transverse sectional views of a thimble and sleeve forming the nozzle of this invention, indicating the adjustment the lumen of the nozzle.

The specific embodiment of my invention chosen for illustration here is a service-line tire gauge, the general construction of the gauge being that shown in my prior application above mentioned. As shown in Fig. 1 such gauges are fitted to the compressed air hose or service line used for filling tires, the gauge being mounted between the hose I leading from the compressor and receiver, and a swivel fitting 2 which leads to the chuck which makes connection with the tire. The .gauge proper is mounted on a fitting 3 which includes an air valve 4 for controlling the flow to the tire, these fittings not being described in detail since they form no part of this invention.

The particular gauge described comprises a moulded plastic case 5. A general view of the moulded case is shown in Fig. 1, and fragmentary cross-sections thereof are shown in Figs. 2 and 3. An inlet air channel 1, leading from the tire connection 2, is moulded into the material of the case.

The frame of the gauge or meter movement fits snugly into the case and comprises an upper plate or disc 8 anda lower plate 9 which carry the pivots on which the rotor l0 and its index hand II are supported. Between these two plates is mounted a center plate I 2. This center plate is in the plane of the rotor, and in it is formed an expansion chamber l3 which directs the air from the nozzle against the rotor, all of the structure described thus far being the same as is shown in my previous application above referred to. As

there pointed out, the periphery [4 of the rotor is knurled or roughened to increase the action of the air jet against it, and the rotor is restrained by a hair spring not shown in the figures of this specification.

The nozzle of this invention is fitted in a hole 15 which is formed through the three plates 8, 9 and I2 of the meter movement and'extends into but not through the case 5. This hole connects with the air channel 7 in the case and the expansion chamber [3 in the center plate I2, and is preferably parallel to the rotor axis. Into the hole is fitted a sleeve II, a flange or fillister head l8 having a screw-driver slot [9. This sleeve should be a tight frictional flt, but not a drive fit, in the hole in the frame.

Within the sleeve l1, and also preferably held by snug frictional fit is hollow thimble 20, the open end of which connects as shown with the air channel I. The upper end is closed and is provided with a head 22 which fits within a recess or counter bore in the head of I8 of the sleeve, and is also supplied with a screw-driver slot 23.

Apertures are formed in the side of the thimble and sleeve in the plane of the rotor l and the center plate l2, these apertures preferably being formed by assembling the thimble within the sleeve and slitting both of them with a metalslitting saw. It is a matter of choice whether the slit be made on an are, as shown in Figs. and 6, by running the saw directly toward the axis of the thimble and sleeve, or whether the nozzle assembly be run across the saw edge, giving a straight-edge slit as shown in Fig. 4.. In either case the sleeve may be turned about the thimble (or the thimble turned within the sleeve) as shown in Figs. 4 and 6, to reduce the lumen of the nozzle. Furthermore, the sleeve and thimble may be rotated as a unit to project the jet from the nozzle against the wall of the expansion chamber to give the proper scale reading.

It will be obvious that other forms of aperture in the sleeve and thimble can be used and similarly adjusted. I prefer the slit arrangement, however, since it gives an aperture in which equal angles between thimble and sleeve give equal increments in lumen. Furthermore, the kerf of a slitting saw may be maintained to a high degree of accuracy even though the slit be but five or siX thousandths of an inch in width, whereas it is difficult to keep small drills on center, and the diameter of a drilled hole varies with the eccentricity of the drill. For this reason, slits are to be preferred to other forms of apertures since they can be more cheaply and accurately made.

I claim:

which is provided with 1. A nozzle for a fluid meter comprising a rotor against which the fluid is directed to give an indication of flow, said nozzle comprising an inner cylindrical thimble having a closed end and an opening opposite the closed end to receive the fluid, and an outer sleeve surrounding and rotatable about said thimble, said thimble and sleeve being provided with apertures having sides parallel with the axis of the cylinder and end walls at right angles to said sides which may be brought into register to provide a jet directed against said rotor and adjustable by relative rotation of said thimble and sleeve to regulate flow therethrough and said thimble being frictionally engaged within said sleeve so as to rotate normally therewith.

2. A nozzle for a fluid meter comprising a rotor against which the fluid is directed to give an indication of flow, said nozzle comprising an inner cylindrical thimble having a closed end and an opening opposite the closed end to receive the fluid, and an outer sleeve surrounding and rotatable about said thimble, said thimble and sleeve being provided with registrable rectangular slots transverse to their axes and forming a jet directed against said rotor and having a rectangular lumen adjustable by relative rotation of said thimble and sleeve and said thimble being frictionally engaged within said sleeve so as to rotate normally therewith.

3. The combination with a fluid meter comprising a rotor pivoted on an axis and mounted in a frame, of a nozzle comprising a sleeve rotatably mounted in said frame parallel with said axis, and a hollow thimble rotatably'mounted within said sleeve, said sleeve and thimble having rectangular openings therein in the plane of the rotor which are registrable by relative rotation of sleeve and thimble to form a nozzle aperture of variable rectangular lumen, the angle of said aperture with respect to said rotor being variable by joint rotation of said sleeve and thimble.

4. The combination with a fluid meter having a rotor and a channel for directing fluid against said rotor, of a nozzle comprising a hollow thimble connecting with said channel, a sleeve surrounding said thimble in frictional engagement therewith and rotatable thereabout, a friction bearing supporting said sleeve, said sleeve and thimble having registrable rectangular apertures co-acting with said channel to direct fluid against said rotor, and means for rotating said thimble and sleeve individually or as a unit to change the direction and amount of flow against said rotor.

MORRIS C. 

